In a rocker joint pin type silent chain, the connecting pins used to connect interleaved, adjacent rows of link plates are composed of pairs of pins, one pin being a so-called joint pin, which is press-fit into guide plates on both sides of the chain, and the other being a so-called rocker pin, which has a convex surface in rocking engagement with a facing convex surface of a joint pin.
A known silent chain having rocker joint pins is described in Japanese Laid-Open Patent Publication No. 2000-130518. In this chain, link plates, each having a pair of teeth and a pair of pin holes, are connected to one another by connecting pins inserted into pin holes. Guide links are disposed on outer sides of the outermost link plates. Links having differently protruding inner flanks are randomly mixed in the chain.
Another known silent chain having rocker joint pins is described in U.S. Pat. No. 6,432,011. This chain is composed of link modules composed of link plates each including a pair of front and rear engagement portions and a pair of front and rear pin holes. The rocker joint pins in this chain include a first rocker joint pin composed of a first longer pin and a first shorter pin, each having a different first thickness in the direction of the pitch of the chain, and a second rocker joint composed of a second longer pin and a second shorter pin, each having a different second thickness in the pitch direction. The second thickness of the second longer or shorter pin is different from the first thickness of a corresponding one of the first longer and shorter pins. The first joint rocker pin and the second rocker joint pin are arranged in an irregular pattern along the length of the silent chain.
Assembly of the silent chain of Japanese Laid-Open Patent Publication No. 2000-130518 is difficult because, although it is desirable to have a large number of different engagement patterns, achieving this objective requires the incorporation of a large number of different link plates into the chain, increasing the number of different parts required for assembly of the chain.
In the rocker joint silent chain of U.S. Pat. No. 6,432,011, the chain pitch is limited to three different chain pitches, so that periodic engagement noise cannot be adequately suppressed.
This invention addresses the above-described problems in the prior art. By combining the effects of an arrangement of differently shaped link plates with an arrangement of rocker pin and joint pin combinations, a large number of different, engagement pitches can be realized, and periodic engagement noise can be significantly reduced. Further, by adopting a randomized arrangement of the link plates and connecting pins, periodic engagement noise can be still further reduced.